In the past, primarily carbon-containing cobalt-chrome-molybdenum alloys, also called model casting alloys, have been used for the manufacture of prosthetic structures for removable dental prostheses. Known alloys of this type contain 0.3 to 0.6 % carbon, up to 1% each silicon and manganese, 27 to 32% chromium, 3 to 8% molybdenum, remainder cobalt with the unavoidable impurities occasioned by the manufacture ("Das Dental Vademecum", a list of dental and dental-technology working means and materials, editor: Federal Board of Doctors (Federal Association of German Dentists, BDZ), edition 1989/90). The molybdenum content of these alloys can be replaced entirely or partially by tungsten according to DIN 13912, part 2 (outline). However, tungsten is only approximately half as effective as molybdenum in its effect on corrosion resistance. These alloys generally exhibit satisfactory mechanical and corrosion-chemical properties for the purpose intended. However, their relatively low deformability, with values for the elongation at rupture (A.sub.5) between 2 and 6%, permits only slight plastic deformations without the danger of rupture.
In order to improve the deformability which is necessary e.g. in aligning work on the holding clamps of prosthetic frames, titanium-containing alloys and other materials have been suggested in which a part of the carbon was replaced by nitrogen (see Published German Patent Application DE 22 25 557 C2). These alloys exhibit relatively high values for the 0.2% permanent elongation limit (around 650 N/mm.sup.2) and elongations at rupture up to 12%. It would be very desirable to raise the 0.2% permanent elongation limit of these alloys to values above 670 N/mm.sup.2 for the manufacture of lighter and more graceful prosthetic frames, by means of the addition of nitrogen. However, this is not possible because the solubility limit with nitrogen contents above 0.3%. This renders the manufacture of pore-free cast objects impossible.